BRUSSELS  More than 10,000 people, most elderly and living alone, may have died in France during this month's blistering heat wave, French health officials said Thursday. The revised estimate would make it one of the worst such disasters in modern history.

French President Jacques Chirac promises measures to remedy defects in the health service after thousands have died in recent heat.

By Pierre Verdy, AP

The number of dead, about half in the Paris area, is far more than in other European countries that have suffered through the deadly heat. Countries to the south, such as Spain and Portugal, are more accustomed to the heat; temperatures in Britain and Germany have not been as severe.

Even so, officials were struggling Thursday to find reasons for the calamity. Among them: no air conditioning in many homes and hospitals; a population lacking experience with the need to stay hydrated in heat waves; and the slow response of a nation on holiday.

President Jacques Chirac, who has been feeling the heat for a lack of government action, addressed the nation live on TV and radio for the first time since the crisis began in late July. He promised that "everything will be done to remedy the inadequacies that we have seen in our health system."

But Chirac, tanned and rested after a three-week vacation in Canada that drew criticism from the press and political opponents, offered few details. It was unclear how he would juggle budget cuts and improve health services.

France's health care system is consistently ranked among the best in the world. Its hospitals, however, do not have air conditioning because of the fear that cooling systems spread bacteria. A large number of hospital beds are left vacant in August, when many doctors and nurses go on vacation.

The estimated death toll has risen steadily in the past week, even as the mercury has dropped. On Aug. 14, the number of dead was estimated to be up to 3,000. Three days later, the figure was put at 5,000. On Thursday, the minister for the elderly, Hubert Falco, said "most probably" 10,000 people died from temperatures as high as 104.

The number of heat-related fatalities is 10 times as large as the record 1,021 recorded in the USA in all of 1995. The figure also dwarfs the losses this summer in Italy, where news reports estimate 2,000 died; Portugal, where an estimated 1,316 died; and Spain, where at least 100 died.

Most of the people who succumbed to the heat were elderly and living alone in apartments that typically do not have air conditioning. Critics turned on the French themselves for going on vacation while leaving aged relatives alone.

"These dramas again shed light on the solitude of many of our aged or handicapped citizens," Chirac said.

One health official has resigned: Lucien Abenhaim, chief of the national health service, stepped down Monday.

The public outcry is getting louder.

"Chirac counts the dead," read a headline in the left-leaning daily Liberation, over a cartoon of Chirac finger-pointing with the prime minister and the health minister. And Le Parisien, a daily paper in Paris, ran a poll showing that 51% of the French believe the government's response to the disaster was inadequate and incompetent.

Chirac said he has asked for a study of the crisis and its causes from his embattled government. He promised proposals by October to better care for France's growing numbers of elderly people.

After weeks of 100-plus temperatures earlier this month, the mercury hovered around a pleasant 75 degrees Thursday. But France was still struggling with the enormous number of bodies.

A refrigerated warehouse next to the fruit and vegetable market in Rungis, near Orly airport, has been turned into a makeshift morgue. Mortuaries and cemeteries have called staff members back from vacation and are remaining open longer to handle about 900 funerals a week in Paris — double the usual number for August.